The correct answer is: B. fcr > fcs > fcl
Modulus of rupture (fcr) is the maximum bending stress that a material can withstand before it fails. Splitting strength (fcs) is the maximum tensile stress that a material can withstand before it fails when subjected to a splitting force. Direct tensile strength (fcl) is the maximum tensile stress that a material can withstand before it fails when subjected to a direct tensile force.
In general, fcr > fcs > fcl. This is because the material is more likely to fail in tension than in compression. When a material is subjected to a bending force, the outer fibers of the material are in tension, while the inner fibers are in compression. The material is more likely to fail in tension, so the modulus of rupture is typically greater than the splitting strength.
The direct tensile strength is typically the lowest of the three values, because the material is subjected to a pure tensile force. This means that there is no compressive force to help support the material, so it is more likely to fail.
It is important to note that these are just general trends, and the actual values for fcr, fcs, and fcl will vary depending on the material.